Concrete form stripping valve



March 26, 1968 E. R. GARRETSON ET AL. 3,374,983

CONCRETE FORM STRIPPING VALVE Filed Aug. 9, 1965 INVENTORS ELDR/DG'E R.GARRETSON WILLIAM S SPURR CHESTER L. WARD ATTOR YS United States PatentOfiice 3,374,983 Patented Mar. 26, 1968 CONCRETE FORM STRIPPING VALVEEldridge R. Garretson, North Kingsville, William S. Spurr,

Geneva, and Chester L. Ward, Ashtabula, Ohio, assignors to The MoldedGlass Company, Ashtabula,

Ohio, a corporation of Ohio Filed Aug. 9, 1965, Ser. No. 478,149

8 Claims. (Cl. 249205) I ABSTRACT OF THE DISCLOSURE A valve for concretemolding form having a stripping aperture, such valve having a domed headand cylindrical stem, with the stem having an internal air passage fromthe free end to a point just beneath the head. The valve is inserted inthe mold aperture and the stern has an external rib which will passthrough the aperture by resilient deformation but engage With theunderside for permanent assembly to the form in the normal use of thesame.

This invention relates to a concrete form of the type which is strippedor separated from the set concrete shape formed by the same by supplyingcompressed air or other fluid to the interface of the form and theshape.

A well-known and widely used form of this type is the pan or domeemployed in building construction to form waffleslab floors, and thisuse serves further to illustrate that an installation can be ofconsiderable size and thus involve a very large number of individualforms to be handled, installed or applied, and finally stripped orremoved. In such floor construction, the pans are inverted to formdownwardly open recesses at the underside of the floor, and they areprovided with generally central apertures in their uppermost bottomwalls for the noted air stripping. The apertures or blow holes must beshielded in one manner or another to prevent clogging or blockage by theconcrete slurry poured against the pans, while permitting andfacilitatingthe initial entry of the air applied under pressure frombelow between the pan and the overlying concrete shape.

It isthus known, as shown by US. Patent No. 2,850,- 785, to make such apan with an internal nipple at the aperture, to receive the compressedair line nozzle, and provide an adhesive patch to be applied externallyover the aperture, with the patch being of rough or irregular characterso that the contact with the pan surface around the aperture isintermittent and the dic'sontinuities effectively provide passages forthe discharge of air from about the periphery of the patch and henceto-the interface of the pan and the concrete shape. This practicerequires that there be a separate supply ofpatches available at theparticular work location, and the application thereof to the individualpans=in the installation prior to pouring constitutes a separateoperation to be performed. More recently, such concrete forming pans ordomes have been made with simple apertures, that is, without attached orintegral nipples, and, molded plastic plugs of various configurationshave. been employed in lieu of the noted adhesive patches. Such plugshave generally been in the form of thin domes with fluted ornon-cylindrical stems, as shownby'U.S. Patent No. 3,151,374, these stemsbeing adapted to be temporarily inserted through the apertures with theprotective domes externally shielding the apertures. Such stem may havesome force engagement with the pan in the aperture, but the assembly isnevertheless still temporary, the stem requiring its noted irregularshape to permit passage of the compressed air from the inside to theoutside of the pan in use and ready to be stripped. Not only are theseplugs thus also of impermanent assembly, they further equally constitutea second component source to be supplied and handled in much the samemanner as the adhesive patches.

The plug type of shield has also proved to be rather erratic in itsperformance, with some provision usually made to facilitate the initialentry of the air beneath the dome portion for efficient air stripping,so that the plug will in this sense be equivalent to the crinkled orirregular adhesive patch as above noted. The underside of the dome insuch a plug has therefore been made with projections in a variety ofconfigurations serving to space portions of the dome and thereby defineair escape or discharge passages. The known plugs of this class,however, have not proved to be wholly satisfactory and reliable, andtheir use in any event still inherently involves a separate supply andhandling in view of the temporary nature of their association with theforming pans.

It is a primary object of this invention to provide an improved assemblyof concrete forming pan and the like and a permanently associated valvedevice for stripping in the manner discussed. The permanent character ofthis assembly has been shown to greatly simplify the use of the forms,for example, in the noted waflle slab forming operation where the numberof pans or domes employed is very considerable, especially in regard toactual time on the job. The valve devices can thus be associated withthe pans conveniently at a storage or other supply location, without anyfurther operation in the actual placement of the pans in the forminginstallation of the same, there being no chance of accidentaldislodgement of the devices as assembled with the pans.

Another object of the invention is to provide an assembly of a concreteforming pan and valve device as set forth in which the mechanical designof the latter is such to assure uniform proper performance over longperiods of use. The valve device, nevertheless, can very readily andeconomically be manufactured.

It is also an object of the present invention to provide such a valvedevice which is capable of use in association with concrete formapertures of varying extent or, in other words, with forms of differentwall thicknesses at the aperture portions thereof. A

Other objects and adavntages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends the invention,then comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawing setting forth in detail a certain illustrative embodiment of theinvention, this being indicative, however, of but one of the variousways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a perspective view, on a relatively reduced scale, of atypical concrete forming pan equipped with a stripping valve inaccordance with the present invention;

FIG. 2 is a vertical sectional view of the pan through the valve, withthis view fragmented for convenience;

FIG. 3 is an elevation of the valve device separate from the pan; and

FIG. 4 is a bottom plan view of such valve device.

Referring now to the drawing in detail, the concrete form designatedgenerally by reference numeral 10 is a pan or dome of the type commonlyused for example in forming waffle slab floors in building construction.This pan has a peripheral flange 11 for support and attachment in theparticular operative disposition desired, and the actual bottom 12 ofthe pan in the floor example at least will be uppermost. Insofar as thepresent invention is concerned, the material of which the pan is made isnot important and any suitable material can be used, such as metal orfiber reinforced plastic, both of which are presently employed for thepurpose.

There is a central aperture provided in the pan bottom 12, and a valvedevice designated generally by reference numeral 13 is assembled withthe pan at such aperture. Valve device 13 should preferably be made of adurable, corrosion-resistant, and resilient material, such as neoprenerubber, which has been found to be quite satisfactory in these respectsand lends itself to ready manufacture of the valve by conventionalmolding techniques.

This valve device, more particularly, comprises a circular head portion14, which can be slightly convex as shown, for a reason to be laterexplained, and a stem portion 15 as an integral central extension ofreduced size. Stem portion 15 is cylindrical and provided with acontinuous external rib 16 at a predetermined distance along the lengthof such portion from that end thereof joined to the head portion 14. Theother end of the stem portion is preferably provided with a recess 17 asillustrated and there is an axial cylindrical passage 18 extending fromsuch free or exposed end recess substantially the full length of thestem portion to intercept a lateral passage 19 of generally rectangularcross section extending completely diametrically through the stemportion, whereby communication is provided from the free end of thevalve stem portion to a pair of diametrically opposite outletsapproximately at the other end or the juncture with the head portion.

The manner in which the valve device 13 is attached to the pan isbelieved evident from FIG. 2, and it will be appreciated that thisattachment is not difficult to accomplish in view of the resilientlydeformable character of the valve body. The location of the stem portionrib 16 is such to engage with the inner surface of the pan bottom 12about the aperture therein when the head portion 14 is engaged againstthe exterior of the bottom, as shown, with some degree of resilientopposition serving to help maintain the valve device in the desirednormally permanent association with the pan. The slightly convex shapeof the head portion will permit this valve device to be thus assembledwith pans of varying thickness without impairing the permanent characterof the assembly, and it will be further apparent that the ends of thelateral passage 19 are approximately at the outer surface of the panbottom.

Since the manner of use of such a concrete forming pan is well-known, noillustration of a concrete shape has been included in the drawing, itbeing sutficient for the purpose to note again that the pan in the floorconstruction use will be supported in inverted condition as shown inFIG. 1, whereby the head portion of the valve device is at the top whereit will be covered by the poured concrete slurry. The aperture or blowhole is effectively sealed about the lip of the head portion. After theconcrete has set sufliciently for stripping of the pan, the workmanplaces the nozzle of a compressed air line against the end of the stemportion, the recessed formation of the latter assisting suchapplication, and air is then forced through the passages 18 and 19 todischarge at the ends of the latter. The air thus supplied willeffectively break the peripheral seal by pressure deformation of theedge or lip to escape along the outer surface of the pan bottom orbetween the bottom and the formed concrete shape and thus force the panfrom the shape.

It will be noted thatthe stem of the valve device is of approximatelythe same size as the pan aperture, such.

hollow stern being readily compressible by hand for insertion therein,and the head is of radially outwardly tapering thickness to provide aquite thin sealing edge or lip. The convexity of the head is notcritical to performance and could be eliminated if desired, whereby theunderside of this portion would be flat.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. In a molding form for concrete and the like having a fluid strippingaperture, a valve device at the aperture of said form, said valve devicecomprising a head portion and a cylindrical stem portion of relativelyreduced size extending generally centrally from the head portion, bothsaid head and stem portions being made of a resiliently deformablematerial, the stem portion passing through the aperture and the headportion overlying the exterior of the form and obscuring the aperture,and locking means for maintaining the valve device normally permanentlyin such association with the form in use of the latter, the

' stem portion having an internal air passageway extendholding means isan integral part of the resilient stem portion.

3. The combination set forth'in claim 1, wherein the head portion isgenerally convex, with the stem portion 7 extending interiorlytherefrom.

4. The combination set forth in claim 1, wherein the holding means is aperipheral projection on the stem portion and is engaged with theinterior of the form about the aperture in resilient opposition to theengagement of the head portion with the exterior of the form.

5. The combination set forth in claim 1, wherein the free end of thestem portion is provided with a recess to receive an air nozzle, andsaid passageway includes an axial length in communication with saidrecess.

6. The combination set forth in claim 1, wherein said air passagewaycomprises an axial length extending from the exposed free end of thestem portion and a connecting lateral length which extends from saidaxial length to said outlet.

7. The combination set forth in claim 1, wherein said air passagewaycomprises a lateral section extending transversely through the stemportion with its ends generally in diametric opposition, and aconnecting longitudinal section extends from an intersection with thelateral section to the free end of the stem portion.

8. The combination set forth inclaim 7, wherein the holding means is aperipheral projection on the stem portion and so located therealong asto engage the form interior about the aperture in resilient oppositionto the head portion engagement with the form exterior.

References Cited UNITED STATES PATENTS 1,522,780 1/ 1925 Hennessy.

1,983,757 12/1934 Hick.

2,148,084 2/ 1939 Nock.

2,850,785 9/1958 Rushing 249--66 X 2,886,876 5/1959 Wilson 25-120X3,151,374 10/1964 Kersten 249-187 WILLIAM J. STEPHENSON, PrimaryExaminer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,374,983 March 26, 1968 Eldridge R. Garretson et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, line 5, for "The MoldedGlass Company," read The Molded Fiber Glass Company,

Signed and sealed this 8th day of July 1969.

iEAL) ttest:

iward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

ttesting Officer Commissioner of Patents

